[MP1-4838] Volume control no longer functions properly when changing audio device (1 Viewer)

[Rick164]

Hi,

Been debugging an issue with @Virtual in the AudioSwitcher topic and is as follows:

- Start Mediaportal with volume control set to master:

- Test out volume control via keyboard for instance ( + -), will notice your audio device changing volume from sys tray.
- Let Mediaportal run and change your default Windows audio device to something else either via AudioSwitcher plugin or Windows sound panel.
- Test out volume control via keyboard, will notice your volume changing on your old Windows audio device instead and keep the current one as-is.

Now so far it can be inconsistent and looking over the code below can't find any red flags, best guess is that we only set the audio device on startup and hook that up to volume control but don't check for changes afterwards (during volume events).
While it works fine during playback you do lose Mediaportal volume control, anyone have any idea what is causing this?

https://github.com/MediaPortal/MediaPortal-1/blob/master/mediaportal/Core/Player/VolumeHandler.cs

Added Installer to Jira : https://issues.team-mediaportal.com/browse/MP1-4838
Thanks @Rick164

 

[Stéphane Lenclud]

Best guess is that we only set the audio device on startup and hook that up to volume control but don't check for changes afterwards (during volume events).

It seems so.
That's unlikely to be an issue when using an HID remote or HID multimedia keyboard since we don't do anything other than letting the system do volume changes for us.

 

[Rick164]

Yeah that's how I do it at the moment for family and here via Flirc + Harmony which will be either via its bluetooth keyboard or emulated key press.

 

[Sebastiii]

In mediaportal.cs we have that : I think it's here the init is done : line 3123

VolumeHandler.CreateInstance();
GUIGraphicsContext.VolumeHandler = VolumeHandler.Instance;

If we are looking in \mediaportal\Core\DShowNET\Helper\DirectShowUtil.cs line 905

try
                  {
                    // vh.Volume = 19660500 that means Audio endpoint device are not available.
                    if (GUIGraphicsContext.VolumeHandler != null && GUIGraphicsContext.VolumeHandler.Volume == 19660500) // Check if new audio device is connected
                    {
                      Log.Debug("DirectShowUtil: need dispose volume handler value {0}", GUIGraphicsContext.VolumeHandler.Volume);
                      VolumeHandler.Dispose();
                      GUIGraphicsContext.VolumeHandler = VolumeHandler.Instance;
                    }
                    if (GUIGraphicsContext.VolumeHandler != null && GUIGraphicsContext.VolumeHandler.Volume != 19660500 && GUIGraphicsContext.DeviceAudioConnected > 0)
                    {
                      Log.Debug("DirectShowUtil: volume handler value {0}", GUIGraphicsContext.VolumeHandler.Volume);
                      Log.Debug("DirectShowUtil: build the graph for PIN : {0}", pinName);
                      hr = graphBuilder.Render(pins[0]);
                    }
                  }
                  catch (Exception exception)
                  {
                    Log.Warn("DirectShowUtil: Could not initialize volume handler (don't connect Audio Pin) : {0}", exception.Message);
                  }

That part does a reinit, maybe it's possible to reinit differently elsewhere ?

 

[Rick164]

Looked at that and seems we can create a new volume instance but does only help with OSD display but not for the actual volume, think we need a way to re-init it in DirectShowUtil or some event that will trigger if audio device changes (no longer primary).

Ideally the volume control should always change it's default Windows audio device if set to "Default direct sound device" but not sure if that can be done easily.

    private void SetPlaybackDevice(CoreAudioDevice device)
    {
      try
      {
        Log.Debug($"Audio Switcher - setting default playback device to: {device.FullName}");
        device.SetAsDefault();
        Log.Debug($"Device audio connected: {GUIGraphicsContext.DeviceAudioConnected}");

        if (Settings.LAVbitstreamPerDevice)
        {
          SetLavBitstreamSettings(device.FullName);
        }

        Log.Debug("Resetting volume control");
        Thread.Sleep(1000);
        VolumeHandler.Dispose();
        Thread.Sleep(1000);
        VolumeHandler.CreateInstance();
        Log.Debug("Volume control reset");
      }
      catch (Exception ex)
      {
        Log.Error("Error occured during SetPlaybackDevice()");
        Log.Error(ex.Message);
      }
    }

 

[Sebastiii]

So ideally we should kept some volume instance value before the change and restore it on new instance
But i think we need also to do : GUIGraphicsContext.VolumeHandler = VolumeHandler.Instance;
What do you think ?

Edit : we need to get and restore GUIGraphicsContext.VolumeHandler.Volume i think.

 

[Rick164]

Agree, we need to tie up the new instance however requires:

- A way of knowing if it has changed and update accordingly
- Change volume on the default Windows device if user has set video audio device to Default or new option in GUI where you can select which device to use like with video audio renderer (default directsound / device X etc..)

Now the Win32 audio API is pretty hard to deal with and couldn't find any clear examples for events so far, this was one of the reasons I went with AudioSwitcher core API which has easy control and can be events driven (also async for most parts in latest beta)
Integration with that probably won't work well with Mediaportal but the developer is very helpful as he wrote the wrapper for the Win32 audio API so might possibly have a solution so we could ask him on Github

 

[Stéphane Lenclud]

If we are considering using a C# audio library we may want to take a look at NAudio and CScore.
See https://forum.team-mediaportal.com/...now-playing-window.135659/page-2#post-1206732
I believe NAudio is older and more popular but I quite like CScore notably because of their nicer spectrum visualizer samples.
I've recently switched one of my projects from NAudio to CScore and that was easily done.

 

[Stéphane Lenclud]

I've just cleaned up my usage of CScore to handle volume changes and default device change notification.
It's now implemented in that AudioManager class. That could be a useful reference if ever we need to implement something similar in MP1.

 

[mm1352000]

@Rick164
If you're going down the path of investigating proper handling for audio device changes, I think our current code that tracks audio device connection/disconnection could do with a bit of love. Specifically:

• Find an alternative way to enumerate audio devices at startup that doesn't require DirectShow (ie. replace -->this<--)
• When an audio device is removed, detect whether that device was being used as the audio renderer for the playing media. Only stop playback if the device is being used. It might be possible to detect this better with a completely different method such as with DirectShow graph events (eg. this one).